International Journal of Architecture, Engineering and ConstructionVol 7, No 1, March 2018, 20-25

Construction of a Prefabricated Reinforced Concrete

Dock of a Fishing Harbor

Malek Jedidi1,2,∗ and Badis Moalla1

1Department of Civil Engineering, Higher Institute of Technological Studies of Sfax, Tunisia

2National Engineering School of Tunis, University Tunis El Manar, Tunisia

Abstract: This paper presents the results of a follow-up study of the construction of the fishing harbor of Sidi Mansour located11 km north of Sfax. The manufacturing of a 361.5-meter-long dock was made from three types of reinforced concrete blocks.The Dreux-Gorisse method was used to determine the cement and aggregates content for the concrete mix. A compressiontest machine was used to determine the values of compressive strength of cylindrical concrete specimens (16 cm × 32 cm) atthe ages of 4, 7 and 28 days. The consistency as well as workability of fresh concrete were identified using a slump test.

Keywords: Fishing harbor, dock, Dreux-Gorisse method, concrete block, compression strength test, slump test

DOI: http://dx.doi.org/10.7492/IJAEC.2018.003

1 INTRODUCTION

A harbor is a facility for receiving ships and transferring car-go. They are usually situated at the edge of an ocean, sea,river, or lake. Ports often have cargo handling equipment suchas cranes (operated by longshoremen) and forklifts for use inloading/unloading of ships, which may be provided by privateinterests or public bodies. Often, canneries or other processingfacilities will be located nearby. Harbor pilots and tugboatsare often used to maneuver large ships in tight quarters asthey approach and leave the docks.Several recent studies have produced a considerable body of

work related to the fishing harbors (Ben-Yami 1985; Pollnac1994; Pomeroy 1994; Singh and Ham 1995). In fact, fishingharbor provides dedicated port and supporting infrastructurefacilities required by the fishing and fish processing industries,for:

1. the safe berthing of fishing vessels, where the vessels candischarge their catches, take on bunker, water, ice andother necessary provisions, and berth for idle times andrepairs;

2. the use of public utilities by provision of networks fordistribution to port customers of electricity, water, aswell as environmental protection facilities required forgarbage collection and disposal, wastewater and sewagedischarge and treatment, and oil reception from vessels;

3. the development of fish processing industries and mar-kets and related highest hygienic standards by provisionof land areas and optimized land use planning, includingtransportation and communication facilities.

The role of the fishing harbor may be considered as the inter-face between the netting of fish and its consumption. In manycases, the fishing harbor is also the focal point of pollution,both of the surrounding environment and the fishery productsit produces. Many fishing harbors are also the source of ma-jor impacts on the physical and biological coastal environment(Sciortino 2010).

A fishing harbor should serve as an integrated fish industrywith operational facilities, provision of repair and maintenanceservices for the fishing fleet and fish storage, and processingand sales activities. Consequently, the fishing port complexis subject to multipurpose use involving all functions and ser-vices directly and indirectly connected with the fishing andfish industry.

In today’s world of increased environmental awareness, afishing harbor must be planned, designed and managed in har-mony with both the physical and biological coastal environ-ments. At each stage of the process, whether it is planning, de-sign or management, both technical and non-technical personsbecome involved in the process. Within government depart-ments, whether they be technical (fisheries or public works)or non-technical (budget or finance), it is not uncommon fornon-technical persons to affect the outcome of technical de-cisions. Fisheries departments worldwide generally have tomanage and maintain harbors and landing places using non-engineering civil servants.

The present paper presents the results of an experimen-tal study carried out in the fishing harbor of Sidi Mansour.The manufacturing of a 361.5-meter-long dock was made fromthree types of reinforced concrete blocks. A compression test

*Corresponding author. Email: malekjedidi@yahoo.fr

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machine and a slump test were used to determine respective-ly the compressive strength of cylindrical concrete specimensat the ages of 4,7 and 28 days and the workability of freshconcrete.

2 HARBOR DOCK

The harbor dock is a structure of embarkation or landing ofsinners witch ensures the ship/land connection. It supportsthe lands at the limit of the water and provides the supportdevice.

The support function of the ship is always ensured by thestructure, the mooring can be carried out on separate points,the connection with the land is ensured either by the workor by the platform directly behind him. Land support canbe provided either by the structure or by an ancillary work(embankment slope).

In the case of a prefabricated reinforced concrete block dock(case of our project), the dock wall was consisted of prefabri-cated concrete blocks, hollowed out or not, stacked under thewater on top of each other, above a well-adjusted seat.The empty blocks were filled with embankment, and the

whole was joined together by a reinforced concrete copingbeam cast in situ above the level water level after backfillplacement.

3 PREPARATION OF CONCRETE MIX:DREUX-GORISSE METHOD

3.1 Materials

The cement used was a CEM I 42.5, in conformity with theStandard NF EN 197-1 (NF EN 197-1 2012), produced by theCement Company of GABES. The physical and mechanicalcharacteristics of cement are shown in Table 1.

Table 1. Physical and mechanical properties of cement

Properties Absolute density (g/cm3) Bulk density (g/cm3) Blaine specific surface (cm2/g) True class of strength (MPa)Value 3.10 1.05 3100 45

Natural sand 0/4 was used as fine aggregates. Gravel 4/12and gravel 12/20 were used as coarse aggregates. Particlessize distribution of sand and gravel was determined by theclassical method of sieving described in the standard NF EN933-1(NF EN 933-1 2012). The physical characteristics of theaggregates used in the preparation of concrete mix are shownin Table 2.

Table 2. Physical characteristics of aggregates

Aggregates Absolute density(g/cm3)

Bulk density(g/cm3)

Finessemodules

Sand 0/4 2.45 1.62 2.53Gravel 4/12 2.60 1.60 -Gravel 12/20 2.60 1.60 -

3.2 Cement and Water Content

The dosage of water and cement depends on the target re-sistance, and the quality of the cement and aggregates. Thecement/water ratio (C/W) is approximately evaluated usingthe overage compressive strength σ′28 and the required plas-ticity using the equation (1):

σ′28 = G.σc

(C

W− 0.5

)(1)

where σ′28 is the required overage compressive strength at 28days in MPa; σc is the true cement class at 28 days in MPa; Cis the cement content in kg/m3; W is the total water contentin Kg/m3; G is the granular coefficient which represents theaggregates quality.

Table 3 gives the values of granular coefficient G accordingto the aggregates quality and dimensions. It is concluded thatthe granular coefficient G is equal to 0.6 since the dimensionsof the aggregates used for the manufacture of concrete arebetween 25mm and 40mm.

Table 3. Values of granular coefficient G

Aggregatesquality

Aggregates dimensions DD ≤ 16mm 25 mm ≤ D ≤ 40 mm D ≥ 63mm

Very good 0.55 0.60 0.65Good 0.45 0.50 0.55

Fairly good 0.35 0.40 0.45

For safety, the required overage compressive strength at 28days represents an increase of 6 MPa of the desired resistance.So the required overage compressive strength is calculated us-ing the equation (2):

σ′28 = σc + 6 (2)

From equation (1), the report C/W can be calculated usingthe equation (3):

C

W=

σ′28G.σc

+ 0.5 =40 + 6

0.6x 45= 2.2 (3)

we note from equation (3) that the cement content increaseswhen the required overage compressive strength of the con-crete is high. Conversely, the cement content decreases as thestrength of the cement increases. For a required overage com-pressive strength, there is also less need for cement when thequality or size of aggregates increase.

According to the value of the Cement/Water ratio (C/W =

2.2) and the desired workability (6 cm), the cement contenthas been determined using the chart (Dreux 1981) depicted inFigure 1. The value found is C = 400 kg/m3+ liquifer.

From equation (3), the water content can be calculated usingthe equation (4):

C

W= 2.2⇒ w =

C

2.2=

400

2.2= 182l (4)

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Figure 1. Cement content to use in respect to the requiredC/W ratio and the workability

3.3 Aggregates Content

The granular reference curve OAB was drawn on the samegraph as the granulometric curves of the components aggre-gates (Figure 2). The point B is placed at100% and it corre-sponds to the dimension D of the greatest aggregate and thepoint O is placed at 0%. The abscissa and the ordinate of thebreaking point A are defined by the equation (5) and (6):

XA =D

2(forD ≤ 20) (5)

YA = 50−√D+K+KS +KP (6)

where K is a corrective term which depends on the cementcontent, the clamping effectiveness, the rolled or crushed ag-gregates shape and also on the sand fineness modulus.If the sand finesse module FM is strong (coarse sand), an

additional correction KS will be made to raise the point A asdefined by the equation (7):

KS = 6FM − 15 (7)

If the quality of the concrete is to be specified pumpable,it will be advisable to confer on the concrete the maximumof plasticity and to enrich it in sand compared to a concreteof current quality. It will be possible for this to increase thecorrective term K of the value Kp = +5 to +10 according tothe desired degree of plasticity.By replacing the terms of equations (5) and (6) by their

values, we find:XA =D

2=

20

2Y A = 50−

√20− 4 + 0.18

⇒

{XA = 10

Y A = 41.7

Figure 2. The granular reference curve OAB drawn on thesame graph as the granulometric curves of thecomponents aggregates

Once the granular reference curve OAB has be drawn, thedividing lines between each aggregates type were traced byjoining the point at 95% of the granular curve of the first ag-gregates type to the point at 5% of the granular curve of thefollowing aggregates type and so on. According to Figure 2,the percentage of sand and the two types of gravel are respec-tively g1 = 36%, g2 = 20% and g3 = 44%.The cement grains net volume is given by the equation (8):

c =C

ρC(8)

where ρC is the cement grains specific mass equal to 3.100and C is the cement dosage equal to 400.The net volume of all the aggregates is given by the equation

(9):

V = 1000 γ − c (9)

where γ is the compactness coefficient depends on the typeof vibration, the consistency of the mix and the maximumdiameter of the aggregates.The net volumes of each aggregates are then given using the

equation (10):v1 ≥ g1Vv2 ≥ g2Vv3 ≥ g3V

(10)

To get the mass of each aggregate, the net volumes havebeen multiplied by the specific masses of each of this aggre-gate. Table 4 gives the mass of each aggregate used for makinga cubic meter of concrete.

Table 4. Summary table for calculating aggregates masses according to the Dreux-Gorisse method

Aggregate Percentageof aggregate

Compactnesscoefficient

Cement grainsnet volume (L/m3)

Net volume ofaggregates (L/m3)

Net volume ofeach aggregate (L/m3)

Mass of eachaggregate (kg)

Sand 36%0.815 129 680

247 605Gravel 1 20% 137 357Gravel 2 44% 302 786

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3.4 Preparation of dock blocks

The types and dimensions of blocks realized in this projectare presented in Table 5. The pouring of each block was com-pleted without interruption. All the precautions were taken(watering on concreting area) to prevent the concrete fromdrying out during the first days of hardening. The particlesize composition approved by the engineer has been respectedto allow, from the dosages and qualities of imposed cement,to obtain the required minimum strengths.

Table 5. Types and dimensions of blocks

Type Number Dimension (m) Volume (m3)

A 250 3.200 × 1.500 × 1.000 4.800B 250 2.650 × 1.500 × 1.000 3.975C 250 2.100 × 1.500 × 1.000 3.150

Well cared metal forms were used to ensure the formworkof the different blocks (Figure 3). The surfaces of the sheetsin contact with the concrete do not have mesh and meet theflatness conditions normally accepted for the locksmith struc-tures.

Figure 3. Different types of blocks and their formwork. (a)Block type A; (b) Block type B; (c) Block type C

The formwork preparation was carried out according to thefollowing steps (Figure 4):1. The forms were carefully cleaned to remove stains from

the hydrocarbon products (grease) and remove traces of rust.2. Immediately prior to concrete placement, the forms were

carefully brushed to remove dust and debris of all kinds.3. A layer of oil has been applied to the internal surfaces

of the formwork in order to facilitate the operation of blocksdemolding.4. Clean the platform of all elements that can act on the

lower surface of the block before putting the formwork in place.

5. The formwork was moved to the intended pouring loca-tion using a loader. A polyethylene film has been placed underthe formwork to facilitate the handling of the hardened block.

Figure 4. Formwork preparation. (a) Cleaning of the plat-form; (b) Establishment of a polyethylene film;(c) Moving of the formwork

3.5 Pouring Concrete

The concrete pouring of each block was completed withoutinterruption. All precautions have been taken to ensure (dayby day) the watering on concrete area to prevent drying outof the concrete during the first days of curing.A ready mixed concrete was used for pouring blocks as

shown in Figure 5. The vibration was provided by electricconcrete vibrator with needle flexible shaft. The vibrator nee-dle was immersed vertically or at a low angle, then slowly backup. The successive vibration points should not be too close tothe formwork. The surfaces were treated using a ruler and atrowel to provide a flat and smooth surface.

Figure 5. Pouring of concrete

After twenty-four hours, formworks can be safely removed.On each block, a number and the date of its manufacture wasnoted. After 7 days of pouring, the blocks were transportedto the storage area using a loader.

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4 CONCRETE TESTS

4.1 Compressive Strength Test

A sample collection of concrete was performed compulsorilyfor each pouring of 50 m3 or at the request of the represen-tative of the administration. The molds of the cylindricalconcrete specimens collected (Figure 6) were crushed in labo-ratories by three samples at the ages of 4 days, 7 days and 28days to control the resistance of cast concrete on site.

Figure 6. Cylindrical concrete specimens 16 cm × 32 cm

The compressive strength of specimens was determined bydestructive testing with a compression test machine accordingto the requirements of NF EN 12390-3 (NF EN 12390-3 2009).Progressive loading with a rate of 0.5 MPa/s was applied tothe crushing of the specimen. The compressive strength valuewas read directly from the computer screen (Figure 7).

Figure 7. Compression strength test

According to the results shown in Table 6, it is noted thatthe average compressive strength of the specimens is equal to12.50 MPa at the age of 4 days, 25.000 MPa at the age of 7days and 35.100 MPa at the age of 28 days. we also note thatthe concrete can reach 50% of its compressive strength at theage of 4 days, which allowed us to transport the blocks after 7days of pouring the concrete. At the age of 28 days, the valueof the compressive strength is even greater than the minimumresistance required (35.100 MPa > 30.000 MPa).

Table 6. Compressive strength of specimens at the ages of 4, 7 and 28 days

Age of specimen Specimen Density (g/cm3) Maximum load (kg) Compressive strength (MPa)

4 daysC1 2.47 36700 18.350C2 2.46 36200 18.100C3 2.46 39000 19.500

7 daysC1 2.38 43400 21.700C2 2.40 51000 25.500C3 2.41 54600 27.300

28 daysC1 2.39 72100 36.050C2 2.43 70700 35.350C3 2.41 67800 33.900

4.2 Slump Test

Concrete slump test is an on-the-spot test to determine theconsistency as well as workability of fresh concrete. This testplays a vital role in ensuring immediate concrete quality in aconstruction project. It is used almost in every constructionsites.

Slump test is very simple and easy to handle. It also de-mands comparatively less equipment and can be done in ashort period of time. These advantages of slump test havemade it very popular all over the world. In slump test, worka-bility of concrete is not measured directly. Instead, consisten-cy of concrete is measured which gives a general idea aboutthe workability condition of concrete mix.

Concrete slump test was determined according to the re-quirements of NF EN 12350-2 (BS EN 12350-2 2009) in thefollowing steps (Figure 8):

1. Cleaned carefully the internal surface of the mould andapplied an oil on the surface.

2. Filled the mould with fresh concrete in three layers. Asteel rod with diameter of 16 mm was used to tamp eachlayer. The rod is rounded at the ends and the tampingshould be done uniformly. Removed excess concrete af-ter filling the mold with fresh concrete.

3. Lifted gently the mould in the vertical direction andthen unsupported concrete will slump.

4. Measured the slump of the concrete by measuring thedistance from the top of the slumped concrete to thelevel of the top of the slump cone.

According to the measurement result, we note that the work-ability of fresh concrete is medium (slump value 50 mm -90 m-m). Indeed, the mixes are typically used for normal reinforcedconcrete placed with vibration.

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Figure 8. Concrete slump test

5 CONCLUSION

The present paper has presented results of an experimentalstudy carried out in the fishing harbor of Sidi Mansour locat-ed 12 km north-east of Sfax, on a broad promontory forminga protuberance in relation to the general orientation of thecoast. The following conclusions have been drawn from theinvestigation.1. The Dreux-Gorisse method was used to determine the

cement and aggregates content for the concrete mix.2. The values of cement and water content for the concrete

mix are respectively C = 400 kg/m3+ liquifer and W = 182l.3. The masses of the different aggregates were determined

by the Dreux-Gorisse method.4. The manufacturing of the harbor dock needs three types

of reinforced concrete blocks A, B and C of volumes respec-tively 4.800 m3, 3.975 m3 and 3.150 m3.5. The values of compressive strength of cylindrical concrete

specimens (16 cm × 32 cm) at the ages of 4, 7 and 28 daysare in accordance with the specifications of the project.6. The workability of fresh concrete were identified using a

slump test. The slump value is equal to 58 mm. The results re-veal that workability is medium (slump value 50 mm∼90 mm)and the mixes are typically used for normal reinforced concreteplaced with vibration.

ACKNOWLEDGMENTS

The authors express our thanks and gratitude for all whohelped us to prepare this study, especially the Agency of theHarbors and Fishing Facilities (APIP) and the civil engineer-

ing department of the higher institute of the technologicalstudies of Sfax for their assistance and contribution to thedevelopment of this work.

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Ben-Yami, M., Anderson, A.M. (1985). “Community fisheriescenters: Guidelines for establishment and operation.” Fish-eries Technical Paper 264, Food and Agriculture Organiza-tion, Rome, Italy.

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Dreux, G. (1981). Nouveau Guide Du Béton, 3rd Edition. Ey-rolles, Paris, France.

NF EN 12390-3 (2009). Testing Hardened Concrete - Part 3:Compression Strength of Test Specimens. European Com-mittee for Standardization, Brussels, Belgium.

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